1. Field of the Invention
The present invention relates to an FM-CW radar apparatus that uses a frequency-modulated (FM) continuous wave (CW) as a signal for transmission and, more particularly, to a DBF radar apparatus that performs digital beam forming.
2. Description of the Related Art
A conventional DBF radar apparatus comprises: a transmitter section for radiating an electromagnetic wave as a transmit signal; an array antenna comprising a plurality of antenna elements for receiving, as a received signal, the electromagnetic wave reflected by an object; a plurality of input terminals connected to the respective antenna elements; an output terminal which is selectively connected by a switching means to one of the plurality of input terminals; and a receiver section in which the received signal obtained from the output terminal is downconverted by using a portion of the transmitted signal and the resulting difference signal representing the difference between the transmitted signal and the received signal is converted into a digital signal, wherein the distance to or the relative velocity of the object is detected by applying prescribed processing to the digital signal obtained from the receiver section (refer, for example, to Publication of Japanese Unexamined Patent Application No. 11-160423).